The turf maintenance field involves a wide range of equipment used to promote turf growth and to thereafter maintain the grass surface forming the upper portion of the turf. For example, aerators are used to punch holes in the ground to relieve soil compaction in and beneath the turf. Mowers are used to cut the grass surface of the turf to a desired height. Fertilizers apply nutrients and pesticides to the turf to encourage grass growth and to prevent or limit damage to the grass by insects.
In order to intelligently diagnose the health of the turf, various measuring instruments are used to measure various parameters related to the health of the turf. For example, many known soil moisture sensors determine the moisture content of the soil using Timed Domain Reflectometry (TDR). A TDR sensor involves sticking a probe assembly comprising various probes into the ground. When the probes are pulsed with electrical energy while they are inserted into the ground, a reading can be taken from which the moisture content of the soil can be derived.
A penetrometer is a type of instrument used to measure soil compaction. Like the TDR sensor described above, a penetrometer has a probe assembly that must be pushed into the ground in order for the penetrometer to take a reading. The penetrometer includes a load cell that measures the resistance the probe assembly encounters when entering the ground. This resistance is a measure of how compacted the soil is at the spot where the probe assembly has been inserted into the ground.
Other turf measurement instruments are known. A spectrometer known as the GreenSeeker® uses light emitting diodes (LED) to generate red and near infrared (NIR) light. The light generated is reflected off of the grass surface of the turf and is measured by a photodiode. Red light is absorbed by plant chlorophyll as an energy source during photosynthesis. Therefore, healthy turf absorbs more red light and reflects larger amounts of NIR than turf that is unhealthy. Thus, the GREENSEEKER® Instrument provides a measurement of the health or vigor of the turf. Other spectrometers besides the GreenSeeker® are also known in the art.
A turf measurement instrument like the GreenSeeker® spectrometer operates without requiring physical penetration of the ground. A spectrometer works simply by shining light at the turf and measuring the reflected light from the grass. Thus, in the past a spectrometer type instrument has simply been mounted on a mobile frame and driven over an area of turf whose health is to be measured.
However, for a TDR soil moisture sensor, the probe assembly must be inserted into the ground in order for the device to operate. Thus, in the past, such an instrument has traditionally been hand held with the probe assembly being manually inserted or pushed into the soil at various desired spots. This is done by a walking operator who holds the instrument in his or her hands and who manually pushes the probe assembly into the soil to undertake a soil moisture measurement and then manually pulls the probe assembly out of the soil at the conclusion of the measurement. This is a difficult and tiring task. Moreover, when measuring the soil moisture content over a large area of turf, such as a golf course, it is extremely time consuming and laborious.
Penetrometers used to measure soil compaction have in the past been mounted on vehicles rather than being hand-held. However, like a TDR soil moisture sensor, the probe assembly of the penetrometer must be inserted into the ground in order to take a reading. Thus, with a vehicle mounted penetrometer, the vehicle must be stopped at each location where a reading is desired, the penetrometer must then be inserted into the ground, the reading is then taken, and then the penetrometer must be pulled out of the ground, all with the vehicle remaining stopped. Then, and only then, can the vehicle be driven to the next spot where a reading is to be taken. While the operator need not walk the entire area to be measured, the need to stop the vehicle at each spot where the penetrometer is to be inserted into the ground still makes the act of measuring a large area of turf a time consuming one.